snapshot of https://github.com/toeverything/AFFiNE.git (canary, 2026-09-16; blobs > 131072B omitted)

blocksuite/affine/blocks/surface/src/utils/points-on-curve/curve-to-bezier.ts

@@ -0,0 +1,51 @@
+import type { Point } from '../rough/geometry.js';
+
+function clone(p: Point): Point {
+  return [...p] as Point;
+}
+
+export function curveToBezier(
+  pointsIn: readonly Point[],
+  curveTightness = 0
+): Point[] {
+  const len = pointsIn.length;
+  if (len < 3) {
+    throw new Error('A curve must have at least three points.');
+  }
+  const out: Point[] = [];
+  if (len === 3) {
+    out.push(
+      clone(pointsIn[0]),
+      clone(pointsIn[1]),
+      clone(pointsIn[2]),
+      clone(pointsIn[2])
+    );
+  } else {
+    const points: Point[] = [];
+    points.push(pointsIn[0], pointsIn[0]);
+    for (let i = 1; i < pointsIn.length; i++) {
+      points.push(pointsIn[i]);
+      if (i === pointsIn.length - 1) {
+        points.push(pointsIn[i]);
+      }
+    }
+    const b: Point[] = [];
+    const s = 1 - curveTightness;
+    out.push(clone(points[0]));
+    for (let i = 1; i + 2 < points.length; i++) {
+      const cachedVertArray = points[i];
+      b[0] = [cachedVertArray[0], cachedVertArray[1]];
+      b[1] = [
+        cachedVertArray[0] + (s * points[i + 1][0] - s * points[i - 1][0]) / 6,
+        cachedVertArray[1] + (s * points[i + 1][1] - s * points[i - 1][1]) / 6,
+      ];
+      b[2] = [
+        points[i + 1][0] + (s * points[i][0] - s * points[i + 2][0]) / 6,
+        points[i + 1][1] + (s * points[i][1] - s * points[i + 2][1]) / 6,
+      ];
+      b[3] = [points[i + 1][0], points[i + 1][1]];
+      out.push(b[1], b[2], b[3]);
+    }
+  }
+  return out;
+}